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glib/glib/gspawn.c
Simon McVittie 6e480634c6 g_child_watch_source_new: Document restrictions for POSIX platforms 
The warnings issued when dealing with waitpid() raising ECHILD are
somewhat misleading: there are lots of reasons why waitpid() might
fail in this way, and we can't tell which one has happened.
In particular, passing a non-child or a non-pid, waiting for the same
pid elsewhere, or creating a duplicate watch for the same pid would
all fail in the same way.

Consolidate the restrictions into one place, and change all the other
places they were (or should have been!) mentioned to point to
that one place.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Reviewed-by: Philip Withnall <withnall@endlessm.com>
Bug: https://bugzilla.gnome.org/show_bug.cgi?id=723743
2017-10-12 12:22:27 +01:00

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/* gspawn.c - Process launching
*
* Copyright 2000 Red Hat, Inc.
* g_execvpe implementation based on GNU libc execvp:
* Copyright 1991, 92, 95, 96, 97, 98, 99 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h> /* for fdwalk */
#include <dirent.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif /* HAVE_SYS_SELECT_H */
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif /* HAVE_SYS_RESOURCE_H */
#include "gspawn.h"
#include "gthread.h"
#include "glib/gstdio.h"
#include "genviron.h"
#include "gmem.h"
#include "gshell.h"
#include "gstring.h"
#include "gstrfuncs.h"
#include "gtestutils.h"
#include "gutils.h"
#include "glibintl.h"
#include "glib-unix.h"
/**
* SECTION:spawn
* @Short_description: process launching
* @Title: Spawning Processes
*
* GLib supports spawning of processes with an API that is more
* convenient than the bare UNIX fork() and exec().
*
* The g_spawn family of functions has synchronous (g_spawn_sync())
* and asynchronous variants (g_spawn_async(), g_spawn_async_with_pipes()),
* as well as convenience variants that take a complete shell-like
* commandline (g_spawn_command_line_sync(), g_spawn_command_line_async()).
*
* See #GSubprocess in GIO for a higher-level API that provides
* stream interfaces for communication with child processes.
*
* An example of using g_spawn_async_with_pipes():
* |[<!-- language="C" -->
* const gchar * const argv[] = { "my-favourite-program", "--args", NULL };
* gint child_stdout, child_stderr;
* GPid child_pid;
* g_autoptr(GError) error = NULL;
*
* // Spawn child process.
* g_spawn_async_with_pipes (NULL, argv, NULL, G_SPAWN_DO_NOT_REAP_CHILD, NULL,
* NULL, &child_pid, NULL, &child_stdout,
* &child_stderr, &error);
* if (error != NULL)
* {
* g_error ("Spawning child failed: %s", error->message);
* return;
* }
*
* // Add a child watch function which will be called when the child process
* // exits.
* g_child_watch_add (child_pid, child_watch_cb, NULL);
*
* // You could watch for output on @child_stdout and @child_stderr using
* // #GUnixInputStream or #GIOChannel here.
*
* static void
* child_watch_cb (GPid pid,
* gint status,
* gpointer user_data)
* {
* g_message ("Child %" G_PID_FORMAT " exited %s", pid,
* g_spawn_check_exit_status (status, NULL) ? "normally" : "abnormally");
*
* // Free any resources associated with the child here, such as I/O channels
* // on its stdout and stderr FDs. If you have no code to put in the
* // child_watch_cb() callback, you can remove it and the g_child_watch_add()
* // call, but you must also remove the G_SPAWN_DO_NOT_REAP_CHILD flag,
* // otherwise the child process will stay around as a zombie until this
* // process exits.
*
* g_spawn_close_pid (pid);
* }
* ]|
*/
static gint g_execute (const gchar *file,
gchar **argv,
gchar **envp,
gboolean search_path,
gboolean search_path_from_envp);
static gboolean fork_exec_with_pipes (gboolean intermediate_child,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
gboolean cloexec_pipes,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *standard_input,
gint *standard_output,
gint *standard_error,
GError **error);
G_DEFINE_QUARK (g-exec-error-quark, g_spawn_error)
G_DEFINE_QUARK (g-spawn-exit-error-quark, g_spawn_exit_error)
/**
* g_spawn_async:
* @working_directory: (type filename) (nullable): child's current working directory, or %NULL to inherit parent's
* @argv: (array zero-terminated=1): child's argument vector
* @envp: (array zero-terminated=1) (nullable): child's environment, or %NULL to inherit parent's
* @flags: flags from #GSpawnFlags
* @child_setup: (scope async) (nullable): function to run in the child just before exec()
* @user_data: (closure): user data for @child_setup
* @child_pid: (out) (optional): return location for child process reference, or %NULL
* @error: return location for error
*
* See g_spawn_async_with_pipes() for a full description; this function
* simply calls the g_spawn_async_with_pipes() without any pipes.
*
* You should call g_spawn_close_pid() on the returned child process
* reference when you don't need it any more.
*
* If you are writing a GTK+ application, and the program you are spawning is a
* graphical application too, then to ensure that the spawned program opens its
* windows on the right screen, you may want to use #GdkAppLaunchContext,
* #GAppLaunchcontext, or set the %DISPLAY environment variable.
*
* Note that the returned @child_pid on Windows is a handle to the child
* process and not its identifier. Process handles and process identifiers
* are different concepts on Windows.
*
* Returns: %TRUE on success, %FALSE if error is set
**/
gboolean
g_spawn_async (const gchar *working_directory,
gchar **argv,
gchar **envp,
GSpawnFlags flags,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
GError **error)
{
g_return_val_if_fail (argv != NULL, FALSE);
return g_spawn_async_with_pipes (working_directory,
argv, envp,
flags,
child_setup,
user_data,
child_pid,
NULL, NULL, NULL,
error);
}
/* Avoids a danger in threaded situations (calling close()
* on a file descriptor twice, and another thread has
* re-opened it since the first close)
*/
static void
close_and_invalidate (gint *fd)
{
if (*fd < 0)
return;
else
{
(void) g_close (*fd, NULL);
*fd = -1;
}
}
/* Some versions of OS X define READ_OK in public headers */
#undef READ_OK
typedef enum
{
READ_FAILED = 0, /* FALSE */
READ_OK,
READ_EOF
} ReadResult;
static ReadResult
read_data (GString *str,
gint fd,
GError **error)
{
gssize bytes;
gchar buf[4096];
again:
bytes = read (fd, buf, 4096);
if (bytes == 0)
return READ_EOF;
else if (bytes > 0)
{
g_string_append_len (str, buf, bytes);
return READ_OK;
}
else if (errno == EINTR)
goto again;
else
{
int errsv = errno;
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_READ,
_("Failed to read data from child process (%s)"),
g_strerror (errsv));
return READ_FAILED;
}
}
/**
* g_spawn_sync:
* @working_directory: (type filename) (nullable): child's current working directory, or %NULL to inherit parent's
* @argv: (array zero-terminated=1): child's argument vector
* @envp: (array zero-terminated=1) (nullable): child's environment, or %NULL to inherit parent's
* @flags: flags from #GSpawnFlags
* @child_setup: (scope async) (nullable): function to run in the child just before exec()
* @user_data: (closure): user data for @child_setup
* @standard_output: (out) (array zero-terminated=1) (element-type guint8) (optional): return location for child output, or %NULL
* @standard_error: (out) (array zero-terminated=1) (element-type guint8) (optional): return location for child error messages, or %NULL
* @exit_status: (out) (optional): return location for child exit status, as returned by waitpid(), or %NULL
* @error: return location for error, or %NULL
*
* Executes a child synchronously (waits for the child to exit before returning).
* All output from the child is stored in @standard_output and @standard_error,
* if those parameters are non-%NULL. Note that you must set the
* %G_SPAWN_STDOUT_TO_DEV_NULL and %G_SPAWN_STDERR_TO_DEV_NULL flags when
* passing %NULL for @standard_output and @standard_error.
*
* If @exit_status is non-%NULL, the platform-specific exit status of
* the child is stored there; see the documentation of
* g_spawn_check_exit_status() for how to use and interpret this.
* Note that it is invalid to pass %G_SPAWN_DO_NOT_REAP_CHILD in
* @flags, and on POSIX platforms, the same restrictions as for
* g_child_watch_source_new() apply.
*
* If an error occurs, no data is returned in @standard_output,
* @standard_error, or @exit_status.
*
* This function calls g_spawn_async_with_pipes() internally; see that
* function for full details on the other parameters and details on
* how these functions work on Windows.
*
* Returns: %TRUE on success, %FALSE if an error was set
*/
gboolean
g_spawn_sync (const gchar *working_directory,
gchar **argv,
gchar **envp,
GSpawnFlags flags,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
gchar **standard_output,
gchar **standard_error,
gint *exit_status,
GError **error)
{
gint outpipe = -1;
gint errpipe = -1;
GPid pid;
fd_set fds;
gint ret;
GString *outstr = NULL;
GString *errstr = NULL;
gboolean failed;
gint status;
g_return_val_if_fail (argv != NULL, FALSE);
g_return_val_if_fail (!(flags & G_SPAWN_DO_NOT_REAP_CHILD), FALSE);
g_return_val_if_fail (standard_output == NULL ||
!(flags & G_SPAWN_STDOUT_TO_DEV_NULL), FALSE);
g_return_val_if_fail (standard_error == NULL ||
!(flags & G_SPAWN_STDERR_TO_DEV_NULL), FALSE);
/* Just to ensure segfaults if callers try to use
* these when an error is reported.
*/
if (standard_output)
*standard_output = NULL;
if (standard_error)
*standard_error = NULL;
if (!fork_exec_with_pipes (FALSE,
working_directory,
argv,
envp,
!(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
(flags & G_SPAWN_SEARCH_PATH) != 0,
(flags & G_SPAWN_SEARCH_PATH_FROM_ENVP) != 0,
(flags & G_SPAWN_STDOUT_TO_DEV_NULL) != 0,
(flags & G_SPAWN_STDERR_TO_DEV_NULL) != 0,
(flags & G_SPAWN_CHILD_INHERITS_STDIN) != 0,
(flags & G_SPAWN_FILE_AND_ARGV_ZERO) != 0,
(flags & G_SPAWN_CLOEXEC_PIPES) != 0,
child_setup,
user_data,
&pid,
NULL,
standard_output ? &outpipe : NULL,
standard_error ? &errpipe : NULL,
error))
return FALSE;
/* Read data from child. */
failed = FALSE;
if (outpipe >= 0)
{
outstr = g_string_new (NULL);
}
if (errpipe >= 0)
{
errstr = g_string_new (NULL);
}
/* Read data until we get EOF on both pipes. */
while (!failed &&
(outpipe >= 0 ||
errpipe >= 0))
{
ret = 0;
FD_ZERO (&fds);
if (outpipe >= 0)
FD_SET (outpipe, &fds);
if (errpipe >= 0)
FD_SET (errpipe, &fds);
ret = select (MAX (outpipe, errpipe) + 1,
&fds,
NULL, NULL,
NULL /* no timeout */);
if (ret < 0)
{
int errsv = errno;
if (errno == EINTR)
continue;
failed = TRUE;
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_READ,
_("Unexpected error in select() reading data from a child process (%s)"),
g_strerror (errsv));
break;
}
if (outpipe >= 0 && FD_ISSET (outpipe, &fds))
{
switch (read_data (outstr, outpipe, error))
{
case READ_FAILED:
failed = TRUE;
break;
case READ_EOF:
close_and_invalidate (&outpipe);
outpipe = -1;
break;
default:
break;
}
if (failed)
break;
}
if (errpipe >= 0 && FD_ISSET (errpipe, &fds))
{
switch (read_data (errstr, errpipe, error))
{
case READ_FAILED:
failed = TRUE;
break;
case READ_EOF:
close_and_invalidate (&errpipe);
errpipe = -1;
break;
default:
break;
}
if (failed)
break;
}
}
/* These should only be open still if we had an error. */
if (outpipe >= 0)
close_and_invalidate (&outpipe);
if (errpipe >= 0)
close_and_invalidate (&errpipe);
/* Wait for child to exit, even if we have
* an error pending.
*/
again:
ret = waitpid (pid, &status, 0);
if (ret < 0)
{
if (errno == EINTR)
goto again;
else if (errno == ECHILD)
{
if (exit_status)
{
g_warning ("In call to g_spawn_sync(), exit status of a child process was requested but ECHILD was received by waitpid(). See the documentation of g_child_watch_source_new() for possible causes.");
}
else
{
/* We don't need the exit status. */
}
}
else
{
if (!failed) /* avoid error pileups */
{
int errsv = errno;
failed = TRUE;
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_READ,
_("Unexpected error in waitpid() (%s)"),
g_strerror (errsv));
}
}
}
if (failed)
{
if (outstr)
g_string_free (outstr, TRUE);
if (errstr)
g_string_free (errstr, TRUE);
return FALSE;
}
else
{
if (exit_status)
*exit_status = status;
if (standard_output)
*standard_output = g_string_free (outstr, FALSE);
if (standard_error)
*standard_error = g_string_free (errstr, FALSE);
return TRUE;
}
}
/**
* g_spawn_async_with_pipes:
* @working_directory: (type filename) (nullable): child's current working directory, or %NULL to inherit parent's, in the GLib file name encoding
* @argv: (array zero-terminated=1): child's argument vector, in the GLib file name encoding
* @envp: (array zero-terminated=1) (nullable): child's environment, or %NULL to inherit parent's, in the GLib file name encoding
* @flags: flags from #GSpawnFlags
* @child_setup: (scope async) (nullable): function to run in the child just before exec()
* @user_data: (closure): user data for @child_setup
* @child_pid: (out) (optional): return location for child process ID, or %NULL
* @standard_input: (out) (optional): return location for file descriptor to write to child's stdin, or %NULL
* @standard_output: (out) (optional): return location for file descriptor to read child's stdout, or %NULL
* @standard_error: (out) (optional): return location for file descriptor to read child's stderr, or %NULL
* @error: return location for error
*
* Executes a child program asynchronously (your program will not
* block waiting for the child to exit). The child program is
* specified by the only argument that must be provided, @argv.
* @argv should be a %NULL-terminated array of strings, to be passed
* as the argument vector for the child. The first string in @argv
* is of course the name of the program to execute. By default, the
* name of the program must be a full path. If @flags contains the
* %G_SPAWN_SEARCH_PATH flag, the `PATH` environment variable is
* used to search for the executable. If @flags contains the
* %G_SPAWN_SEARCH_PATH_FROM_ENVP flag, the `PATH` variable from
* @envp is used to search for the executable. If both the
* %G_SPAWN_SEARCH_PATH and %G_SPAWN_SEARCH_PATH_FROM_ENVP flags
* are set, the `PATH` variable from @envp takes precedence over
* the environment variable.
*
* If the program name is not a full path and %G_SPAWN_SEARCH_PATH flag is not
* used, then the program will be run from the current directory (or
* @working_directory, if specified); this might be unexpected or even
* dangerous in some cases when the current directory is world-writable.
*
* On Windows, note that all the string or string vector arguments to
* this function and the other g_spawn*() functions are in UTF-8, the
* GLib file name encoding. Unicode characters that are not part of
* the system codepage passed in these arguments will be correctly
* available in the spawned program only if it uses wide character API
* to retrieve its command line. For C programs built with Microsoft's
* tools it is enough to make the program have a wmain() instead of
* main(). wmain() has a wide character argument vector as parameter.
*
* At least currently, mingw doesn't support wmain(), so if you use
* mingw to develop the spawned program, it should call
* g_win32_get_command_line() to get arguments in UTF-8.
*
* On Windows the low-level child process creation API CreateProcess()
* doesn't use argument vectors, but a command line. The C runtime
* library's spawn*() family of functions (which g_spawn_async_with_pipes()
* eventually calls) paste the argument vector elements together into
* a command line, and the C runtime startup code does a corresponding
* reconstruction of an argument vector from the command line, to be
* passed to main(). Complications arise when you have argument vector
* elements that contain spaces of double quotes. The spawn*() functions
* don't do any quoting or escaping, but on the other hand the startup
* code does do unquoting and unescaping in order to enable receiving
* arguments with embedded spaces or double quotes. To work around this
* asymmetry, g_spawn_async_with_pipes() will do quoting and escaping on
* argument vector elements that need it before calling the C runtime
* spawn() function.
*
* The returned @child_pid on Windows is a handle to the child
* process, not its identifier. Process handles and process
* identifiers are different concepts on Windows.
*
* @envp is a %NULL-terminated array of strings, where each string
* has the form `KEY=VALUE`. This will become the child's environment.
* If @envp is %NULL, the child inherits its parent's environment.
*
* @flags should be the bitwise OR of any flags you want to affect the
* function's behaviour. The %G_SPAWN_DO_NOT_REAP_CHILD means that the
* child will not automatically be reaped; you must use a child watch
* (g_child_watch_add()) to be notified about the death of the child process,
* otherwise it will stay around as a zombie process until this process exits.
* Eventually you must call g_spawn_close_pid() on the @child_pid, in order to
* free resources which may be associated with the child process. (On Unix,
* using a child watch is equivalent to calling waitpid() or handling
* the %SIGCHLD signal manually. On Windows, calling g_spawn_close_pid()
* is equivalent to calling CloseHandle() on the process handle returned
* in @child_pid). See g_child_watch_add().
*
* %G_SPAWN_LEAVE_DESCRIPTORS_OPEN means that the parent's open file
* descriptors will be inherited by the child; otherwise all descriptors
* except stdin/stdout/stderr will be closed before calling exec() in
* the child. %G_SPAWN_SEARCH_PATH means that @argv[0] need not be an
* absolute path, it will be looked for in the `PATH` environment
* variable. %G_SPAWN_SEARCH_PATH_FROM_ENVP means need not be an
* absolute path, it will be looked for in the `PATH` variable from
* @envp. If both %G_SPAWN_SEARCH_PATH and %G_SPAWN_SEARCH_PATH_FROM_ENVP
* are used, the value from @envp takes precedence over the environment.
* %G_SPAWN_STDOUT_TO_DEV_NULL means that the child's standard output
* will be discarded, instead of going to the same location as the parent's
* standard output. If you use this flag, @standard_output must be %NULL.
* %G_SPAWN_STDERR_TO_DEV_NULL means that the child's standard error
* will be discarded, instead of going to the same location as the parent's
* standard error. If you use this flag, @standard_error must be %NULL.
* %G_SPAWN_CHILD_INHERITS_STDIN means that the child will inherit the parent's
* standard input (by default, the child's standard input is attached to
* /dev/null). If you use this flag, @standard_input must be %NULL.
* %G_SPAWN_FILE_AND_ARGV_ZERO means that the first element of @argv is
* the file to execute, while the remaining elements are the actual
* argument vector to pass to the file. Normally g_spawn_async_with_pipes()
* uses @argv[0] as the file to execute, and passes all of @argv to the child.
*
* @child_setup and @user_data are a function and user data. On POSIX
* platforms, the function is called in the child after GLib has
* performed all the setup it plans to perform (including creating
* pipes, closing file descriptors, etc.) but before calling exec().
* That is, @child_setup is called just before calling exec() in the
* child. Obviously actions taken in this function will only affect
* the child, not the parent.
*
* On Windows, there is no separate fork() and exec() functionality.
* Child processes are created and run with a single API call,
* CreateProcess(). There is no sensible thing @child_setup
* could be used for on Windows so it is ignored and not called.
*
* If non-%NULL, @child_pid will on Unix be filled with the child's
* process ID. You can use the process ID to send signals to the child,
* or to use g_child_watch_add() (or waitpid()) if you specified the
* %G_SPAWN_DO_NOT_REAP_CHILD flag. On Windows, @child_pid will be
* filled with a handle to the child process only if you specified the
* %G_SPAWN_DO_NOT_REAP_CHILD flag. You can then access the child
* process using the Win32 API, for example wait for its termination
* with the WaitFor*() functions, or examine its exit code with
* GetExitCodeProcess(). You should close the handle with CloseHandle()
* or g_spawn_close_pid() when you no longer need it.
*
* If non-%NULL, the @standard_input, @standard_output, @standard_error
* locations will be filled with file descriptors for writing to the child's
* standard input or reading from its standard output or standard error.
* The caller of g_spawn_async_with_pipes() must close these file descriptors
* when they are no longer in use. If these parameters are %NULL, the
* corresponding pipe won't be created.
*
* If @standard_input is NULL, the child's standard input is attached to
* /dev/null unless %G_SPAWN_CHILD_INHERITS_STDIN is set.
*
* If @standard_error is NULL, the child's standard error goes to the same
* location as the parent's standard error unless %G_SPAWN_STDERR_TO_DEV_NULL
* is set.
*
* If @standard_output is NULL, the child's standard output goes to the same
* location as the parent's standard output unless %G_SPAWN_STDOUT_TO_DEV_NULL
* is set.
*
* @error can be %NULL to ignore errors, or non-%NULL to report errors.
* If an error is set, the function returns %FALSE. Errors are reported
* even if they occur in the child (for example if the executable in
* @argv[0] is not found). Typically the `message` field of returned
* errors should be displayed to users. Possible errors are those from
* the #G_SPAWN_ERROR domain.
*
* If an error occurs, @child_pid, @standard_input, @standard_output,
* and @standard_error will not be filled with valid values.
*
* If @child_pid is not %NULL and an error does not occur then the returned
* process reference must be closed using g_spawn_close_pid().
*
* If you are writing a GTK+ application, and the program you are spawning is a
* graphical application too, then to ensure that the spawned program opens its
* windows on the right screen, you may want to use #GdkAppLaunchContext,
* #GAppLaunchcontext, or set the %DISPLAY environment variable.
*
* Returns: %TRUE on success, %FALSE if an error was set
*/
gboolean
g_spawn_async_with_pipes (const gchar *working_directory,
gchar **argv,
gchar **envp,
GSpawnFlags flags,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *standard_input,
gint *standard_output,
gint *standard_error,
GError **error)
{
g_return_val_if_fail (argv != NULL, FALSE);
g_return_val_if_fail (standard_output == NULL ||
!(flags & G_SPAWN_STDOUT_TO_DEV_NULL), FALSE);
g_return_val_if_fail (standard_error == NULL ||
!(flags & G_SPAWN_STDERR_TO_DEV_NULL), FALSE);
/* can't inherit stdin if we have an input pipe. */
g_return_val_if_fail (standard_input == NULL ||
!(flags & G_SPAWN_CHILD_INHERITS_STDIN), FALSE);
return fork_exec_with_pipes (!(flags & G_SPAWN_DO_NOT_REAP_CHILD),
working_directory,
argv,
envp,
!(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
(flags & G_SPAWN_SEARCH_PATH) != 0,
(flags & G_SPAWN_SEARCH_PATH_FROM_ENVP) != 0,
(flags & G_SPAWN_STDOUT_TO_DEV_NULL) != 0,
(flags & G_SPAWN_STDERR_TO_DEV_NULL) != 0,
(flags & G_SPAWN_CHILD_INHERITS_STDIN) != 0,
(flags & G_SPAWN_FILE_AND_ARGV_ZERO) != 0,
(flags & G_SPAWN_CLOEXEC_PIPES) != 0,
child_setup,
user_data,
child_pid,
standard_input,
standard_output,
standard_error,
error);
}
/**
* g_spawn_command_line_sync:
* @command_line: a command line
* @standard_output: (out) (array zero-terminated=1) (element-type guint8) (optional): return location for child output
* @standard_error: (out) (array zero-terminated=1) (element-type guint8) (optional): return location for child errors
* @exit_status: (out) (optional): return location for child exit status, as returned by waitpid()
* @error: return location for errors
*
* A simple version of g_spawn_sync() with little-used parameters
* removed, taking a command line instead of an argument vector. See
* g_spawn_sync() for full details. @command_line will be parsed by
* g_shell_parse_argv(). Unlike g_spawn_sync(), the %G_SPAWN_SEARCH_PATH flag
* is enabled. Note that %G_SPAWN_SEARCH_PATH can have security
* implications, so consider using g_spawn_sync() directly if
* appropriate. Possible errors are those from g_spawn_sync() and those
* from g_shell_parse_argv().
*
* If @exit_status is non-%NULL, the platform-specific exit status of
* the child is stored there; see the documentation of
* g_spawn_check_exit_status() for how to use and interpret this.
*
* On Windows, please note the implications of g_shell_parse_argv()
* parsing @command_line. Parsing is done according to Unix shell rules, not
* Windows command interpreter rules.
* Space is a separator, and backslashes are
* special. Thus you cannot simply pass a @command_line containing
* canonical Windows paths, like "c:\\program files\\app\\app.exe", as
* the backslashes will be eaten, and the space will act as a
* separator. You need to enclose such paths with single quotes, like
* "'c:\\program files\\app\\app.exe' 'e:\\folder\\argument.txt'".
*
* Returns: %TRUE on success, %FALSE if an error was set
**/
gboolean
g_spawn_command_line_sync (const gchar *command_line,
gchar **standard_output,
gchar **standard_error,
gint *exit_status,
GError **error)
{
gboolean retval;
gchar **argv = NULL;
g_return_val_if_fail (command_line != NULL, FALSE);
if (!g_shell_parse_argv (command_line,
NULL, &argv,
error))
return FALSE;
retval = g_spawn_sync (NULL,
argv,
NULL,
G_SPAWN_SEARCH_PATH,
NULL,
NULL,
standard_output,
standard_error,
exit_status,
error);
g_strfreev (argv);
return retval;
}
/**
* g_spawn_command_line_async:
* @command_line: a command line
* @error: return location for errors
*
* A simple version of g_spawn_async() that parses a command line with
* g_shell_parse_argv() and passes it to g_spawn_async(). Runs a
* command line in the background. Unlike g_spawn_async(), the
* %G_SPAWN_SEARCH_PATH flag is enabled, other flags are not. Note
* that %G_SPAWN_SEARCH_PATH can have security implications, so
* consider using g_spawn_async() directly if appropriate. Possible
* errors are those from g_shell_parse_argv() and g_spawn_async().
*
* The same concerns on Windows apply as for g_spawn_command_line_sync().
*
* Returns: %TRUE on success, %FALSE if error is set
**/
gboolean
g_spawn_command_line_async (const gchar *command_line,
GError **error)
{
gboolean retval;
gchar **argv = NULL;
g_return_val_if_fail (command_line != NULL, FALSE);
if (!g_shell_parse_argv (command_line,
NULL, &argv,
error))
return FALSE;
retval = g_spawn_async (NULL,
argv,
NULL,
G_SPAWN_SEARCH_PATH,
NULL,
NULL,
NULL,
error);
g_strfreev (argv);
return retval;
}
/**
* g_spawn_check_exit_status:
* @exit_status: An exit code as returned from g_spawn_sync()
* @error: a #GError
*
* Set @error if @exit_status indicates the child exited abnormally
* (e.g. with a nonzero exit code, or via a fatal signal).
*
* The g_spawn_sync() and g_child_watch_add() family of APIs return an
* exit status for subprocesses encoded in a platform-specific way.
* On Unix, this is guaranteed to be in the same format waitpid() returns,
* and on Windows it is guaranteed to be the result of GetExitCodeProcess().
*
* Prior to the introduction of this function in GLib 2.34, interpreting
* @exit_status required use of platform-specific APIs, which is problematic
* for software using GLib as a cross-platform layer.
*
* Additionally, many programs simply want to determine whether or not
* the child exited successfully, and either propagate a #GError or
* print a message to standard error. In that common case, this function
* can be used. Note that the error message in @error will contain
* human-readable information about the exit status.
*
* The @domain and @code of @error have special semantics in the case
* where the process has an "exit code", as opposed to being killed by
* a signal. On Unix, this happens if WIFEXITED() would be true of
* @exit_status. On Windows, it is always the case.
*
* The special semantics are that the actual exit code will be the
* code set in @error, and the domain will be %G_SPAWN_EXIT_ERROR.
* This allows you to differentiate between different exit codes.
*
* If the process was terminated by some means other than an exit
* status, the domain will be %G_SPAWN_ERROR, and the code will be
* %G_SPAWN_ERROR_FAILED.
*
* This function just offers convenience; you can of course also check
* the available platform via a macro such as %G_OS_UNIX, and use
* WIFEXITED() and WEXITSTATUS() on @exit_status directly. Do not attempt
* to scan or parse the error message string; it may be translated and/or
* change in future versions of GLib.
*
* Returns: %TRUE if child exited successfully, %FALSE otherwise (and
* @error will be set)
*
* Since: 2.34
*/
gboolean
g_spawn_check_exit_status (gint exit_status,
GError **error)
{
gboolean ret = FALSE;
if (WIFEXITED (exit_status))
{
if (WEXITSTATUS (exit_status) != 0)
{
g_set_error (error, G_SPAWN_EXIT_ERROR, WEXITSTATUS (exit_status),
_("Child process exited with code %ld"),
(long) WEXITSTATUS (exit_status));
goto out;
}
}
else if (WIFSIGNALED (exit_status))
{
g_set_error (error, G_SPAWN_ERROR, G_SPAWN_ERROR_FAILED,
_("Child process killed by signal %ld"),
(long) WTERMSIG (exit_status));
goto out;
}
else if (WIFSTOPPED (exit_status))
{
g_set_error (error, G_SPAWN_ERROR, G_SPAWN_ERROR_FAILED,
_("Child process stopped by signal %ld"),
(long) WSTOPSIG (exit_status));
goto out;
}
else
{
g_set_error (error, G_SPAWN_ERROR, G_SPAWN_ERROR_FAILED,
_("Child process exited abnormally"));
goto out;
}
ret = TRUE;
out:
return ret;
}
static gint
exec_err_to_g_error (gint en)
{
switch (en)
{
#ifdef EACCES
case EACCES:
return G_SPAWN_ERROR_ACCES;
break;
#endif
#ifdef EPERM
case EPERM:
return G_SPAWN_ERROR_PERM;
break;
#endif
#ifdef E2BIG
case E2BIG:
return G_SPAWN_ERROR_TOO_BIG;
break;
#endif
#ifdef ENOEXEC
case ENOEXEC:
return G_SPAWN_ERROR_NOEXEC;
break;
#endif
#ifdef ENAMETOOLONG
case ENAMETOOLONG:
return G_SPAWN_ERROR_NAMETOOLONG;
break;
#endif
#ifdef ENOENT
case ENOENT:
return G_SPAWN_ERROR_NOENT;
break;
#endif
#ifdef ENOMEM
case ENOMEM:
return G_SPAWN_ERROR_NOMEM;
break;
#endif
#ifdef ENOTDIR
case ENOTDIR:
return G_SPAWN_ERROR_NOTDIR;
break;
#endif
#ifdef ELOOP
case ELOOP:
return G_SPAWN_ERROR_LOOP;
break;
#endif
#ifdef ETXTBUSY
case ETXTBUSY:
return G_SPAWN_ERROR_TXTBUSY;
break;
#endif
#ifdef EIO
case EIO:
return G_SPAWN_ERROR_IO;
break;
#endif
#ifdef ENFILE
case ENFILE:
return G_SPAWN_ERROR_NFILE;
break;
#endif
#ifdef EMFILE
case EMFILE:
return G_SPAWN_ERROR_MFILE;
break;
#endif
#ifdef EINVAL
case EINVAL:
return G_SPAWN_ERROR_INVAL;
break;
#endif
#ifdef EISDIR
case EISDIR:
return G_SPAWN_ERROR_ISDIR;
break;
#endif
#ifdef ELIBBAD
case ELIBBAD:
return G_SPAWN_ERROR_LIBBAD;
break;
#endif
default:
return G_SPAWN_ERROR_FAILED;
break;
}
}
static gssize
write_all (gint fd, gconstpointer vbuf, gsize to_write)
{
gchar *buf = (gchar *) vbuf;
while (to_write > 0)
{
gssize count = write (fd, buf, to_write);
if (count < 0)
{
if (errno != EINTR)
return FALSE;
}
else
{
to_write -= count;
buf += count;
}
}
return TRUE;
}
G_GNUC_NORETURN
static void
write_err_and_exit (gint fd, gint msg)
{
gint en = errno;
write_all (fd, &msg, sizeof(msg));
write_all (fd, &en, sizeof(en));
_exit (1);
}
static int
set_cloexec (void *data, gint fd)
{
if (fd >= GPOINTER_TO_INT (data))
fcntl (fd, F_SETFD, FD_CLOEXEC);
return 0;
}
#ifndef HAVE_FDWALK
static int
fdwalk (int (*cb)(void *data, int fd), void *data)
{
gint open_max;
gint fd;
gint res = 0;
#ifdef HAVE_SYS_RESOURCE_H
struct rlimit rl;
#endif
#ifdef __linux__
DIR *d;
if ((d = opendir("/proc/self/fd"))) {
struct dirent *de;
while ((de = readdir(d))) {
glong l;
gchar *e = NULL;
if (de->d_name[0] == '.')
continue;
errno = 0;
l = strtol(de->d_name, &e, 10);
if (errno != 0 || !e || *e)
continue;
fd = (gint) l;
if ((glong) fd != l)
continue;
if (fd == dirfd(d))
continue;
if ((res = cb (data, fd)) != 0)
break;
}
closedir(d);
return res;
}
/* If /proc is not mounted or not accessible we fall back to the old
* rlimit trick */
#endif
#ifdef HAVE_SYS_RESOURCE_H
if (getrlimit(RLIMIT_NOFILE, &rl) == 0 && rl.rlim_max != RLIM_INFINITY)
open_max = rl.rlim_max;
else
#endif
open_max = sysconf (_SC_OPEN_MAX);
for (fd = 0; fd < open_max; fd++)
if ((res = cb (data, fd)) != 0)
break;
return res;
}
#endif
static gint
sane_dup2 (gint fd1, gint fd2)
{
gint ret;
retry:
ret = dup2 (fd1, fd2);
if (ret < 0 && errno == EINTR)
goto retry;
return ret;
}
static gint
sane_open (const char *path, gint mode)
{
gint ret;
retry:
ret = open (path, mode);
if (ret < 0 && errno == EINTR)
goto retry;
return ret;
}
enum
{
CHILD_CHDIR_FAILED,
CHILD_EXEC_FAILED,
CHILD_DUP2_FAILED,
CHILD_FORK_FAILED
};
static void
do_exec (gint child_err_report_fd,
gint stdin_fd,
gint stdout_fd,
gint stderr_fd,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
GSpawnChildSetupFunc child_setup,
gpointer user_data)
{
if (working_directory && chdir (working_directory) < 0)
write_err_and_exit (child_err_report_fd,
CHILD_CHDIR_FAILED);
/* Close all file descriptors but stdin stdout and stderr as
* soon as we exec. Note that this includes
* child_err_report_fd, which keeps the parent from blocking
* forever on the other end of that pipe.
*/
if (close_descriptors)
{
fdwalk (set_cloexec, GINT_TO_POINTER(3));
}
else
{
/* We need to do child_err_report_fd anyway */
set_cloexec (GINT_TO_POINTER(0), child_err_report_fd);
}
/* Redirect pipes as required */
if (stdin_fd >= 0)
{
/* dup2 can't actually fail here I don't think */
if (sane_dup2 (stdin_fd, 0) < 0)
write_err_and_exit (child_err_report_fd,
CHILD_DUP2_FAILED);
/* ignore this if it doesn't work */
close_and_invalidate (&stdin_fd);
}
else if (!child_inherits_stdin)
{
/* Keep process from blocking on a read of stdin */
gint read_null = open ("/dev/null", O_RDONLY);
g_assert (read_null != -1);
sane_dup2 (read_null, 0);
close_and_invalidate (&read_null);
}
if (stdout_fd >= 0)
{
/* dup2 can't actually fail here I don't think */
if (sane_dup2 (stdout_fd, 1) < 0)
write_err_and_exit (child_err_report_fd,
CHILD_DUP2_FAILED);
/* ignore this if it doesn't work */
close_and_invalidate (&stdout_fd);
}
else if (stdout_to_null)
{
gint write_null = sane_open ("/dev/null", O_WRONLY);
g_assert (write_null != -1);
sane_dup2 (write_null, 1);
close_and_invalidate (&write_null);
}
if (stderr_fd >= 0)
{
/* dup2 can't actually fail here I don't think */
if (sane_dup2 (stderr_fd, 2) < 0)
write_err_and_exit (child_err_report_fd,
CHILD_DUP2_FAILED);
/* ignore this if it doesn't work */
close_and_invalidate (&stderr_fd);
}
else if (stderr_to_null)
{
gint write_null = sane_open ("/dev/null", O_WRONLY);
sane_dup2 (write_null, 2);
close_and_invalidate (&write_null);
}
/* Call user function just before we exec */
if (child_setup)
{
(* child_setup) (user_data);
}
g_execute (argv[0],
file_and_argv_zero ? argv + 1 : argv,
envp, search_path, search_path_from_envp);
/* Exec failed */
write_err_and_exit (child_err_report_fd,
CHILD_EXEC_FAILED);
}
static gboolean
read_ints (int fd,
gint* buf,
gint n_ints_in_buf,
gint *n_ints_read,
GError **error)
{
gsize bytes = 0;
while (TRUE)
{
gssize chunk;
if (bytes >= sizeof(gint)*2)
break; /* give up, who knows what happened, should not be
* possible.
*/
again:
chunk = read (fd,
((gchar*)buf) + bytes,
sizeof(gint) * n_ints_in_buf - bytes);
if (chunk < 0 && errno == EINTR)
goto again;
if (chunk < 0)
{
int errsv = errno;
/* Some weird shit happened, bail out */
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Failed to read from child pipe (%s)"),
g_strerror (errsv));
return FALSE;
}
else if (chunk == 0)
break; /* EOF */
else /* chunk > 0 */
bytes += chunk;
}
*n_ints_read = (gint)(bytes / sizeof(gint));
return TRUE;
}
static gboolean
fork_exec_with_pipes (gboolean intermediate_child,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean search_path_from_envp,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
gboolean file_and_argv_zero,
gboolean cloexec_pipes,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
GPid *child_pid,
gint *standard_input,
gint *standard_output,
gint *standard_error,
GError **error)
{
GPid pid = -1;
gint stdin_pipe[2] = { -1, -1 };
gint stdout_pipe[2] = { -1, -1 };
gint stderr_pipe[2] = { -1, -1 };
gint child_err_report_pipe[2] = { -1, -1 };
gint child_pid_report_pipe[2] = { -1, -1 };
guint pipe_flags = cloexec_pipes ? FD_CLOEXEC : 0;
gint status;
if (!g_unix_open_pipe (child_err_report_pipe, pipe_flags, error))
return FALSE;
if (intermediate_child && !g_unix_open_pipe (child_pid_report_pipe, pipe_flags, error))
goto cleanup_and_fail;
if (standard_input && !g_unix_open_pipe (stdin_pipe, pipe_flags, error))
goto cleanup_and_fail;
if (standard_output && !g_unix_open_pipe (stdout_pipe, pipe_flags, error))
goto cleanup_and_fail;
if (standard_error && !g_unix_open_pipe (stderr_pipe, FD_CLOEXEC, error))
goto cleanup_and_fail;
pid = fork ();
if (pid < 0)
{
int errsv = errno;
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FORK,
_("Failed to fork (%s)"),
g_strerror (errsv));
goto cleanup_and_fail;
}
else if (pid == 0)
{
/* Immediate child. This may or may not be the child that
* actually execs the new process.
*/
/* Reset some signal handlers that we may use */
signal (SIGCHLD, SIG_DFL);
signal (SIGINT, SIG_DFL);
signal (SIGTERM, SIG_DFL);
signal (SIGHUP, SIG_DFL);
/* Be sure we crash if the parent exits
* and we write to the err_report_pipe
*/
signal (SIGPIPE, SIG_DFL);
/* Close the parent's end of the pipes;
* not needed in the close_descriptors case,
* though
*/
close_and_invalidate (&child_err_report_pipe[0]);
close_and_invalidate (&child_pid_report_pipe[0]);
close_and_invalidate (&stdin_pipe[1]);
close_and_invalidate (&stdout_pipe[0]);
close_and_invalidate (&stderr_pipe[0]);
if (intermediate_child)
{
/* We need to fork an intermediate child that launches the
* final child. The purpose of the intermediate child
* is to exit, so we can waitpid() it immediately.
* Then the grandchild will not become a zombie.
*/
GPid grandchild_pid;
grandchild_pid = fork ();
if (grandchild_pid < 0)
{
/* report -1 as child PID */
write_all (child_pid_report_pipe[1], &grandchild_pid,
sizeof(grandchild_pid));
write_err_and_exit (child_err_report_pipe[1],
CHILD_FORK_FAILED);
}
else if (grandchild_pid == 0)
{
close_and_invalidate (&child_pid_report_pipe[1]);
do_exec (child_err_report_pipe[1],
stdin_pipe[0],
stdout_pipe[1],
stderr_pipe[1],
working_directory,
argv,
envp,
close_descriptors,
search_path,
search_path_from_envp,
stdout_to_null,
stderr_to_null,
child_inherits_stdin,
file_and_argv_zero,
child_setup,
user_data);
}
else
{
write_all (child_pid_report_pipe[1], &grandchild_pid, sizeof(grandchild_pid));
close_and_invalidate (&child_pid_report_pipe[1]);
_exit (0);
}
}
else
{
/* Just run the child.
*/
do_exec (child_err_report_pipe[1],
stdin_pipe[0],
stdout_pipe[1],
stderr_pipe[1],
working_directory,
argv,
envp,
close_descriptors,
search_path,
search_path_from_envp,
stdout_to_null,
stderr_to_null,
child_inherits_stdin,
file_and_argv_zero,
child_setup,
user_data);
}
}
else
{
/* Parent */
gint buf[2];
gint n_ints = 0;
/* Close the uncared-about ends of the pipes */
close_and_invalidate (&child_err_report_pipe[1]);
close_and_invalidate (&child_pid_report_pipe[1]);
close_and_invalidate (&stdin_pipe[0]);
close_and_invalidate (&stdout_pipe[1]);
close_and_invalidate (&stderr_pipe[1]);
/* If we had an intermediate child, reap it */
if (intermediate_child)
{
wait_again:
if (waitpid (pid, &status, 0) < 0)
{
if (errno == EINTR)
goto wait_again;
else if (errno == ECHILD)
; /* do nothing, child already reaped */
else
g_warning ("waitpid() should not fail in "
"'fork_exec_with_pipes'");
}
}
if (!read_ints (child_err_report_pipe[0],
buf, 2, &n_ints,
error))
goto cleanup_and_fail;
if (n_ints >= 2)
{
/* Error from the child. */
switch (buf[0])
{
case CHILD_CHDIR_FAILED:
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_CHDIR,
_("Failed to change to directory “%s” (%s)"),
working_directory,
g_strerror (buf[1]));
break;
case CHILD_EXEC_FAILED:
g_set_error (error,
G_SPAWN_ERROR,
exec_err_to_g_error (buf[1]),
_("Failed to execute child process “%s” (%s)"),
argv[0],
g_strerror (buf[1]));
break;
case CHILD_DUP2_FAILED:
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Failed to redirect output or input of child process (%s)"),
g_strerror (buf[1]));
break;
case CHILD_FORK_FAILED:
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FORK,
_("Failed to fork child process (%s)"),
g_strerror (buf[1]));
break;
default:
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Unknown error executing child process “%s”"),
argv[0]);
break;
}
goto cleanup_and_fail;
}
/* Get child pid from intermediate child pipe. */
if (intermediate_child)
{
n_ints = 0;
if (!read_ints (child_pid_report_pipe[0],
buf, 1, &n_ints, error))
goto cleanup_and_fail;
if (n_ints < 1)
{
int errsv = errno;
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Failed to read enough data from child pid pipe (%s)"),
g_strerror (errsv));
goto cleanup_and_fail;
}
else
{
/* we have the child pid */
pid = buf[0];
}
}
/* Success against all odds! return the information */
close_and_invalidate (&child_err_report_pipe[0]);
close_and_invalidate (&child_pid_report_pipe[0]);
if (child_pid)
*child_pid = pid;
if (standard_input)
*standard_input = stdin_pipe[1];
if (standard_output)
*standard_output = stdout_pipe[0];
if (standard_error)
*standard_error = stderr_pipe[0];
return TRUE;
}
cleanup_and_fail:
/* There was an error from the Child, reap the child to avoid it being
a zombie.
*/
if (pid > 0)
{
wait_failed:
if (waitpid (pid, NULL, 0) < 0)
{
if (errno == EINTR)
goto wait_failed;
else if (errno == ECHILD)
; /* do nothing, child already reaped */
else
g_warning ("waitpid() should not fail in "
"'fork_exec_with_pipes'");
}
}
close_and_invalidate (&child_err_report_pipe[0]);
close_and_invalidate (&child_err_report_pipe[1]);
close_and_invalidate (&child_pid_report_pipe[0]);
close_and_invalidate (&child_pid_report_pipe[1]);
close_and_invalidate (&stdin_pipe[0]);
close_and_invalidate (&stdin_pipe[1]);
close_and_invalidate (&stdout_pipe[0]);
close_and_invalidate (&stdout_pipe[1]);
close_and_invalidate (&stderr_pipe[0]);
close_and_invalidate (&stderr_pipe[1]);
return FALSE;
}
/* Based on execvp from GNU C Library */
static void
script_execute (const gchar *file,
gchar **argv,
gchar **envp)
{
/* Count the arguments. */
int argc = 0;
while (argv[argc])
++argc;
/* Construct an argument list for the shell. */
{
gchar **new_argv;
new_argv = g_new0 (gchar*, argc + 2); /* /bin/sh and NULL */
new_argv[0] = (char *) "/bin/sh";
new_argv[1] = (char *) file;
while (argc > 0)
{
new_argv[argc + 1] = argv[argc];
--argc;
}
/* Execute the shell. */
if (envp)
execve (new_argv[0], new_argv, envp);
else
execv (new_argv[0], new_argv);
g_free (new_argv);
}
}
static gchar*
my_strchrnul (const gchar *str, gchar c)
{
gchar *p = (gchar*) str;
while (*p && (*p != c))
++p;
return p;
}
static gint
g_execute (const gchar *file,
gchar **argv,
gchar **envp,
gboolean search_path,
gboolean search_path_from_envp)
{
if (*file == '\0')
{
/* We check the simple case first. */
errno = ENOENT;
return -1;
}
if (!(search_path || search_path_from_envp) || strchr (file, '/') != NULL)
{
/* Don't search when it contains a slash. */
if (envp)
execve (file, argv, envp);
else
execv (file, argv);
if (errno == ENOEXEC)
script_execute (file, argv, envp);
}
else
{
gboolean got_eacces = 0;
const gchar *path, *p;
gchar *name, *freeme;
gsize len;
gsize pathlen;
path = NULL;
if (search_path_from_envp)
path = g_environ_getenv (envp, "PATH");
if (search_path && path == NULL)
path = g_getenv ("PATH");
if (path == NULL)
{
/* There is no 'PATH' in the environment. The default
* search path in libc is the current directory followed by
* the path 'confstr' returns for '_CS_PATH'.
*/
/* In GLib we put . last, for security, and don't use the
* unportable confstr(); UNIX98 does not actually specify
* what to search if PATH is unset. POSIX may, dunno.
*/
path = "/bin:/usr/bin:.";
}
len = strlen (file) + 1;
pathlen = strlen (path);
freeme = name = g_malloc (pathlen + len + 1);
/* Copy the file name at the top, including '\0' */
memcpy (name + pathlen + 1, file, len);
name = name + pathlen;
/* And add the slash before the filename */
*name = '/';
p = path;
do
{
char *startp;
path = p;
p = my_strchrnul (path, ':');
if (p == path)
/* Two adjacent colons, or a colon at the beginning or the end
* of 'PATH' means to search the current directory.
*/
startp = name + 1;
else
startp = memcpy (name - (p - path), path, p - path);
/* Try to execute this name. If it works, execv will not return. */
if (envp)
execve (startp, argv, envp);
else
execv (startp, argv);
if (errno == ENOEXEC)
script_execute (startp, argv, envp);
switch (errno)
{
case EACCES:
/* Record the we got a 'Permission denied' error. If we end
* up finding no executable we can use, we want to diagnose
* that we did find one but were denied access.
*/
got_eacces = TRUE;
/* FALL THRU */
case ENOENT:
#ifdef ESTALE
case ESTALE:
#endif
#ifdef ENOTDIR
case ENOTDIR:
#endif
/* Those errors indicate the file is missing or not executable
* by us, in which case we want to just try the next path
* directory.
*/
break;
case ENODEV:
case ETIMEDOUT:
/* Some strange filesystems like AFS return even
* stranger error numbers. They cannot reasonably mean anything
* else so ignore those, too.
*/
break;
default:
/* Some other error means we found an executable file, but
* something went wrong executing it; return the error to our
* caller.
*/
g_free (freeme);
return -1;
}
}
while (*p++ != '\0');
/* We tried every element and none of them worked. */
if (got_eacces)
/* At least one failure was due to permissions, so report that
* error.
*/
errno = EACCES;
g_free (freeme);
}
/* Return the error from the last attempt (probably ENOENT). */
return -1;
}
/**
* g_spawn_close_pid:
* @pid: The process reference to close
*
* On some platforms, notably Windows, the #GPid type represents a resource
* which must be closed to prevent resource leaking. g_spawn_close_pid()
* is provided for this purpose. It should be used on all platforms, even
* though it doesn't do anything under UNIX.
**/
void
g_spawn_close_pid (GPid pid)
{
}
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